Republican presidential nominee Donald Trump called supporters in Grand Junction, Colo., to watch the polls in St. Louis, Philadelphia and Chicago, as he continued to allege that voter fraud is rampant in communities across the country. (Victoria Walker/The Washington Post)

GRAND JUNCTION, Colo. — As Donald Trump continues to insist that voter fraud is "all too common" and could cost him the presidential election, he provided his supporters with a list of three cities where they should watch for corruption on Election Day. Only one is in a battleground state.

"Take a look at St. Louis. Take a look at Philadelphia. Take a look at Chicago," the GOP candidate said at a rally at a regional airport in this western Colorado town on Tuesday afternoon, responding to recent media reports that voter fraud is not as rampant of a problem as Trump has claimed. "... Look, look, if nothing else, people are going to be watching on November 8. Watch Philadelphia. Watch St. Louis. Watch Chicago, watch Chicago. Watch so many other places."

Two of those cities are in states that are not considered competitive. In Missouri, where Trump has a solid lead in the polls, a Republican has won during the past four presidential elections. In Illinois, where Democrat Hillary Clinton has a double-digit lead in most polls, a Democrat has won during the past six presidential elections. Pennsylvania is a state where the race is closer, and Trump is hoping that he can win, although a Democrat has won the past six presidential elections.

For months, Trump has alleged that voter fraud is rampant and, in the past few days, he has suggested that the results on Election Day might not be accurate. At other rallies, Trump has urged his followers to visit polling locations in neighborhoods other than their own and watch — a vague suggestion that some voting rights activists have interpreted as a call for voter intimidation.